JP-C-55-18457 (1980) and U.S. Pat. No. 4,772,409 issued to Mori et al. disclose an organopolysiloxane composition for viscous fluid couplings that consists of an organopolysiloxane liquid and an organopolysiloxane having aromatic amino groups.
U.S. Pat. No. 4,637,889 issued to Kishimoto et al. on Jan. 20, 1987 discloses an organopolysiloxane composition for viscous fluid couplings consisting of an organopolysiloxane liquid, an organosiloxane compound containing zirconium atoms, and an organosiloxane compound containing cerium atoms.
JP-A-04-11696 (1992) discloses an organopolysiloxane composition for viscous fluid couplings consisting of an organopolysiloxane liquid and an organopolysiloxane having at least one silicon-bonded group selected from the group made up of carboxyalkyl groups, halogen-substituted aryl groups, halogen-substituted alkyl groups, and alkyl groups with a carbon number of 5 to 20.
U.S. Pat. No. 5,319,010 issued to Mitani et al. on Jun. 7, 1994 discloses an organopolysiloxane composition for viscous fluid couplings consisting of an organopolysiloxane liquid and an N,N-diaryl-p-arylenediamine compound.
However, all of these organopolysiloxane compositions have the defect that using them at a high temperature for an extended period of time leads to increased torque variation and loss of fluid coupling functionality.
The object of this invention is to provide an organopolysiloxane composition for a viscous fluid coupling that permits little torque variation even when used at a high temperature for an extended period of time.